A new analytical modeling for the determination of thermodynamic quantities of refrigerants

摘要

A new analytical fundamental equation of state (EOS) is presented for fluids. The equation is explicit in the effective molecular potentials and allows calculation of all thermodynamic properties over the whole fluid surface (gas, liquid, supercritical and gas-liquid phase transition). Outside the critical area (+/- 0.05T(c)), it is valid in a vast range of temperature and pressure (0.8T(c)to 7.5T(c)and up to 120P(c),). The EOS is applicable for a variety of refrigerants such as C3H2F4(HFO-1234ze (E)), hydrofluorocarbons (HFCs) including C3F8(R218), C3H2F6(R236ea), C3H2F6(R236fa), C3H3F5(R245ca), C3HF7, C4F8(RC318), C4F10, C5F12, natural refrigerants including NH3, CO2, hydrocarbons, monatomic gases and some other fluids. Calculations of second derivatives properties of fluids are sensitive tests of EOS behavior. Therefore, estimation of the thermodynamic properties including Joule-Thomson coefficient,mu(JT), and speed of sound,w,has been considered.